Fire resistant cable: in the provision test conditions, the test specimen in the flame was burned, in a certain period of time can still maintain the normal operation erformance. Its essential characteristic is that the cable can still maintain the normal operation of the line for some time under the condition of combustion. In layman's terms, in case of fire, the cable will not be burned, the circuit is relatively safe. Therefore, the main difference between the fire retardant cable and flame retardant cable is: the fire resistance cable can maintain normal power supply for a period of time, and the flame retardant cable does not have this characteristic. The cable is mainly used in emergency power supply to the user fire equipment, fire alarm equipment, ventilation and smoke exhaust equipment, light guide lamp, emergency power supply socket, emergency use elevator and other power supply circuit.

General fire resistant cable is divided into class A and class B: class B cable can be at 75℃ to 80℃ flame and the rated voltage withstand the burning for at least 90min and the cable is not breakdown (ie, 3A fuse does not fuse). In improvement of the refractory layer manufacturing process and increase the refractory layer of the method is based on and developed the class a fire resistant cable, it can in the flame of 95℃ - 1 00℃ and rated voltage tolerance combustion for at least 90 min and the cable without breakdown (i.e. 3A fuse fuse). The fire resistance performance of A class fire resistant cable is better than that class B.

Selection items:

(1) when the fire resistant cable is used in the dense cable tunnel, the cable layer, or the oil pipe, the oil depot and so on, we should first choose A class fire resistant cable. In addition to the above circumstances, the number of cable configuration is low, can use B type fire resistant cable.

(2) most of the fire resistant cable is used as the power supply circuit of the emergency power supply, and in the fire required to work properly. Due to in the fire environment temperature sharp rise, in order to guarantee the transmission capacity of lines, and decrease the pressure drop, for long power supply line and strictly limited allowable voltage drop circuit, should enlarge fire-resistant cable section.

(3) refractory cable can not be used as a high temperature resistant cable.

(4) in order to reduce the probability of failure of cable joints in fire accidents, the number of joints should be reduced as far as possible in order to ensure the normal operation of the line in the fire. If you need to do branch wiring, deal with joints to do fireproof treatment.